1. I have installed jackd and used chgroup to audio. Users are a member of the audio group. I have started jackd with "/usr/bin/jackd -d alsa". When I open Rosegarden as a user I get an error message that it cannot connect to jack. However, if I run Rosegarden as root no such message appears. How do I get around this permissions issue?
Run jackd and rosegarden as the same user. My guess is you started jackd as root the first time.
2. I currently do not have a soundcard installed (just onboard audio chip). Is there a recommended virtual keyboard that I could use with rosegarden and jack?
I'm not sure what you mean by virtual keyboard. In rosegarden, you can edit midisequences using the "matrix editor", and use the 'keyboard' on the left side of it. Is that what you want?
chgrp'ing jackd to audio is not very useful, unless you plan to give jackd realtime priorities: http://the.headacher.googlepages.com/jackonvectorlinux